S
P
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L
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Y
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BREE
UNIT 3:
IN THIS UNIT, students explore force, Newton’s laws, air pressure, and
buoyancy by making blimps out of helium-filled balloons.*
UNIT TABLE OF CONTENTS
PLANNING YOUR TIME
Only have one class period
available? Do Sky Floater.
Two class periods? Do Sky
Floater and Making It Real.
Three class periods? Do Sky
Floater, Sky Glider, and
Making It Real.
Four? If your students are
very engaged with this unit
and are able to work with
patience and precision,
include Blimp Jet.
Sky Floater challenge (pages 31–34)
• Overview: Students make a helium-filled Mylar® balloon hover by adding weight
and making it neutrally buoyant. They move the balloon around the room without
touching it by using a sheet of cardboard to make small pockets of low-pressure
air into which the balloon moves.
• Learning outcomes: Students will be able to make a floating object neutrally
buoyant and explain how a balloon moves in response to differences in air
pressure. They will also use the design process to achieve neutral buoyancy
and perfect a technique for moving the balloon.
Sky Glider challenge (pages 35–38)
• Overview: Students apply all they learned in Sky Floater to design and build a
blimp that glides efficiently on a straight course across a room.
• Learning outcomes: Students will be able to explain how drag affects a blimp’s
flight, how its length affects its axis of rotation, and how blimps demonstrate
Newton’s 1st Law. They will also use the design process to design and build a
neutrally buoyant blimp that has a long axis of rotation, is aerodynamic, and is
able to travel in a straight path.
Blimp Jet challenge (pages 39–40)
• Overview: Students add a balloon-powered propulsion system to their blimps to
make them fly across the room under their own power.
Bill D.
Fairgrounds Middle School
Nashua, NH
• Learning outcomes: Students will be able to explain how a blimp demonstrates
Newton’s 3rd Law and describe how they used the design process to get their
“jet” to propel their blimps along a straight course.
Making It Real: The Breezy Blimps Unit (pages 41–42)
• Overview: Students present their blimps and discuss the science and
engineering behind their designs. They also watch two short videos: They meet
a young engineer who keeps a large blimp running smoothly, and they see how
the Design Squad teams use the design process to redesign the blimps they
made to film a rock concert from above.
• Learning outcomes: Students will be able to identify the science concepts
exhibited in their work (e.g., force, Newton’s laws, mass, buoyancy,
aerodynamics, axis of rotation, friction, and air pressure), explain how the
design process encourages them to think creatively to tackle a challenge, point
out how they are thinking and working like engineers, and cite examples of how
engineering is a profession centered on improving people’s lives.
30
* For specific standards, see Appendix, page 48.
“Mylar” is a registered trademark of Dupont Teijin Films U.S. Limited Par tnership.
© 2009 WGBH Educational Foundation.
“ As a teacher for 31 years,
the only thing that really
excited middle school
students is hands-on
activities.”
SKY FLOATER
CHALLENGE
The Challenge: Make a balloon hover at eye level for five seconds, and then
make it move by creating air currents.
Preparation
Copy the Sky Floater handout (one per student).
Visit pbs.org/designsquad and download the following video clips from the
“Teacher’s Guide” page: Band Cam Challenge (1 minute) and Buoyancy
(1½ minutes). Be prepared to project them.
Gather these materials (per student):
• 1 helium-filled Mylar • paper clips of various • corrugated cardboard
(about 8 inches
sizes
balloon
square)
• large binder clip for
• paper
anchoring a balloon • If you have high
• large garbage bags
ceilings, use 2 brooms
(optional)
for storing the
as “jaws” to capture
balloons (12 fit in a • scissors
escaped balloons.
• clear tape
42-gallon bag)
The first task is to weight a
balloon to make it neutrally
buoyant.
NOTE: You can get Mylar balloons at party stores, florists, dollar stores, drug stores, and
supermarkets, often for a dollar each. However, multiple class sections can use the same
balloons for Sky Floater. Have students clean off their balloons at the end of the period so
they’re ready for the next class. If you plan to do Sky Glider as well, stagger the unit with
your different sections since the first class will need their balloons for at least two days.
Helium-filled Mylar balloons reliably provide lift for a week. In our testing, over half our
balloons maintained excellent lift for up to two weeks.
Introduce the challenge (5 minutes)
• Tell students today’s challenge is to first get a helium-filled balloon to hover and
then to move it around the room without anyone touching it. Mention that this
challenge is similar to one that the kids did on the Design Squad TV show.
• Show Band Cam Challenge, in which the Design Squad teams build a blimp to
film a stage concert. Point out that in both the classroom and Design Squad
challenges, kids need to control and direct their balloons.
Do Part 1 of Sky Floater (10 to 15 minutes)
• Show students the materials. Ask: How can you stop a balloon from floating
upward? (Add weight.)
• Distribute the handout and have students do Part 1. Tell them to tie the balloon
ribbon in a bundle close to the neck of the balloon so it doesn’t drag on the
floor or catch on things.
• If drafts are an issue, have students use their bodies to block currents, not
move around too much near the balloon, and work away from air vents, doors,
and windows.
Students make their
balloons hover at face level
for at least five seconds.
© 2009 WGBH Educational Foundation.
• Part 1 takes anywhere from 5 to 15 minutes. Stop everyone after 15 minutes.
Process the science and engineering (10 minutes)
Show the Buoyancy video, which describes how a helium-filled balloon floats. Ask:
• What are the forces affecting this balloon? (Gravity and lift)
• What do you know about these two forces when a balloon is neutrally buoyant
(i.e., when it hovers)? (The force of gravity equals the force of lift.)
31
• Why do the balloons rise? (Air is denser than helium—it has more particles per
unit volume than helium does. The denser air pushes the less-dense helium
aside, producing an upward force called a buoyant force. In our testing, kids
called air a “bully.”)
• How is neutral buoyancy an example of Newton’s 1st Law? (If the forces of lift
and gravity are equal and opposite, the balloon won’t rise or fall.)
Students move their
balloons around the room.
They use cardboard to
create a low-pressure air
pocket. Nearby air moves
into these air pockets,
carrying the balloon with it.
• When will the balloon stop rising? (When it hits the ceiling or rises to a point
where the density of the air outside the balloon equals the density of the helium
inside the balloon. When these two densities are equal, there is no longer a
buoyant force.)
• What steps of the design process did you use to make the balloon neutrally
buoyant? (Identified the problem; brainstormed how to make the balloon hover;
tested different ways to weight the balloon; refined our systems; shared solutions;
etc.)
Give the class a “driving” lesson (5 minutes)
Borrow a neutrally buoyant balloon from one of your students. Ask the class to
predict: How will this balloon move when I fan a piece of cardboard next to the
balloon but not at it? Demonstrate by taking a square of cardboard and sharply
sweeping it alongside the balloon in one swift motion (i.e., no fanning back and
forth). Surprise! The balloon moves unexpectedly toward where you swept the
cardboard. Repeat on the other side, and above and below the balloon.
Explain that the balloon is surrounded by air.
When you sweep the cardboard beside
Lift
the balloon, you temporarily remove some
Air
of the air, producing an area with fewer
air molecules (i.e., lower pressure).
Surrounding air molecules rush in to
Air
equalize the pressure, carrying the balloon
Balloon
with them. By creating a succession of
Movement
low-pressure air pockets, kids can move
the balloons around the room a few inches
Gravity
at a time. End by demonstrating that rapid
fanning at a balloon makes it hard to control the balloon’s movement.
Fanning results in chaotic air currents. They will move a balloon, but in
an unpredictable way.
32
© 2009 WGBH Educational Foundation.
Once they learn how to move
their balloons, students step
them around a partner, one
low-pressure air pocket at
a time.
Do Parts 2 and 3 of Sky Floater (10–15 minutes)
Have students experiment with different techniques for moving a balloon in a circle
around a partner. If time permits, they could also do an obstacle course or race
other teams.
SKYFLOATER
Watch DESIGN SQUAD on PBS or online at pbs.org/designsquad.
Major funding for Design Squad provided by
Additional funding for Design Squad provided by
© 2009 WGBH Educational Foundation. Design Squad is produced by WGBH Boston. Design Squad, AS BUILT ON TV, and associated logos are trademarks of WGBH. All rights reserved. Major funding
for Design Squad is provided by the National Science Foundation, the Intel Foundation, and the Lemelson Foundation. Additional funding is provided by Noyce Foundation, United Engineering Foundation
(ASCE, ASME, AIChE, IEEE, AIME), National Council of Examiners for Engineering and Surveying, ASME, the IEEE, Northrop Grumman, and the Intel Corporation. All third party trademarks are the
property of their respective owners. Used with permission. This Design Squad material is based upon work supported by the National Science Foundation under Grant No. 0810996. Any opinions,
findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
SKY GLIDER
CHALLENGE
The Challenge: Build a blimp that travels in a straight path across the room.
Preparation
Copy the Sky Glider handout (one per student).
Visit pbs.org/designsquad and download the following video clips from the
“Teacher’s Guide” page: Air Resistance (1 minute), Axis of Rotation (1 minute),
and Design Process: Testing the Axis of Rotation (1½ minutes). Be prepared to
project them.
Set up 3–4 launching stations. For each station, you’ll need
2 sheets of corrugated cardboard (approx. 11 x 17 inches),
duct tape, rubber bands, and paper clips.
Gather these materials (per team of two):
• Sky Floater balloons • scissors
• small paper clips
• clear tape
• copier paper
First, students make a
neutrally buoyant blimp out
of two balloons. Many used
a paper tube to connect
their balloons.
Launching Station
Insert the paper clips so the rubber
bands gently lift the launcher's back.
Introduce the challenge (5 minutes)
• Tell students that today’s challenge is to build a blimp that can travel a straight
path across the room. Point out how this activity is similar to the Band Cam
challenge: The blimp must be neutrally buoyant and travel in a predictable way.
• Ask: Who might be interested in using blimps? (People interested in moving
heavy loads and using energy-efficient transportation. Blimps also make excellent
eyes-in-the-sky for things like filming sporting events, TV broadcasts, surveillance,
search-and-rescue missions, and observing wildlife.)
Brainstorm (10 minutes)
Brainstorm air resistance
Tape together the wide faces of two balloons. Set them in motion using the
launcher. Point out that the device launching the balloons is an example of one
object transferring its kinetic energy to another.
• What keeps this pair of balloons from going across the room? (Air resistance)
• Drop a sheet of paper, first with the wide face perpendicular and then with it
parallel to the floor. Ask: Which has the most drag (i.e., a force that resists
an object’s movement)? (There is more drag when the wide face is parallel to
the ground, and the paper falls more slowly.)
• What are some things that are streamlined to cut easily through air or water?
(Sports cars, blimps, submarines, planes, fish, birds, etc.)
• To reduce drag and move efficiently through the air, which face of a balloon
should face forward? (The narrowest one, so that it can slice through air)
© 2009 WGBH Educational Foundation.
• What could you use to firmly hold two balloons in this orientation? (A paper
tube or tubes)
Then, students use a rubber
band-powered launching
station to gently set their
blimps in motion.
• Show Air Resistance in which the Design Squad teams discuss how drag
slows down flying objects.
35
Brainstorm axis of rotation
• Show Design Process: Testing the Axis of Rotation. Point out how the Purple
Team’s blimp is held at just one point, making it easy for the blimp to spin.
• Spin the two balloons with your hands. Ask: Why do they spin so easily? (They
have a short axis of rotation—the point around which an object spins. Also,
there is little force, such as air resistance, stopping the spin.)
• What shape do objects that must travel long distances through the air—such
as javelins, footballs, arrows, and rockets—have in common? (They are much
longer than they are wide.)
Next, students get their
blimps to “fly” straight and
far by streamlining them and
lengthening their axis of
rotation. Some students
used fins to help their blimps
travel straight.
• Show Axis of Rotation, in which the Design Squad teams stabilize a boat by
lengthening its axis of rotation. In Sky Glider, students will lengthen the axis
of rotation to help their blimps travel straight.
Brainstorm the design process
• Brainstorm ways to make a blimp from two balloons so it will have low air
resistance. (Students should suggest designs that have as little material as
possible hitting the air as the blimp moves forward.)
• Brainstorm ways to make a blimp from two balloons so it will travel straight
and not spin. (Students should suggest designs where there is a wide
separation between the balloons.)
Summarize the problem to solve (5 minutes)
• Break the larger challenge into its sub-challenges. Ask: What are some of the
things you’ll need to figure out as you make your blimp? (How to: attach the two
balloons; make them neutrally buoyant; launch them gently; keep them on a
straight course; streamline them so they fly far; etc.)
• To promote creative thinking and foster a sense of ownership, have students
pair up and brainstorm their own ways of turning the materials into a blimp that
can glide straight and far. Distribute the handout and have them sketch their
ideas.
Build, test, and redesign (30 minutes)
Here are some strategies for dealing with issues that may come up during building:
• Travel far: Have students make streamlined designs to reduce air resistance.
• Launch the same way: Remind teams to launch their blimps the same way
every time (i.e., use the same launcher, start from the same position, etc.).
Otherwise, it’s hard to know what affects a blimp’s flight—a design change,
the launcher, or the launching technique.
• Record data: Have teams record the distance traveled and keep track of any
rising, falling, spinning, or traveling in an arc.
36
• Storage: Keep blimps intact until you finish the Making It Real session.
© 2009 WGBH Educational Foundation.
Finally, in Making It Real,
students discuss the science
and engineering behind their
designs and describe how
they are thinking and working
like engineers.
• Travel straight: In our testing, students found that fins helped a blimp glide
straight. As a blimp begins to veer from a straight course, the fin’s wide side
begins to hit a lot of air, taking advantage of drag and producing a force that
helps the blimp resist turning. (NOTE: Wings only provide lift at high air
speeds. Buoyant, lighter-than-air craft, such as blimps, go too slowly to make
use of wings, so wings just add unnecessary, burdensome weight.)
Y
K
S GLIDER
Watch DESIGN SQUAD on PBS or online at pbs.org/designsquad.
Major funding for Design Squad provided by
Additional funding for Design Squad provided by
© 2009 WGBH Educational Foundation. Design Squad is produced by WGBH Boston. Design Squad, AS BUILT ON TV, and associated logos are trademarks of WGBH. All rights reserved. Major funding
for Design Squad is provided by the National Science Foundation, the Intel Foundation, and the Lemelson Foundation. Additional funding is provided by Noyce Foundation, United Engineering Foundation
(ASCE, ASME, AIChE, IEEE, AIME), National Council of Examiners for Engineering and Surveying, ASME, the IEEE, Northrop Grumman, and the Intel Corporation. All third party trademarks are the
property of their respective owners. Used with permission. This Design Squad material is based upon work supported by the National Science Foundation under Grant No. 0810996. Any opinions,
findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.
BLIMP JET
CHALLENGE
The Challenge: Add a jet-propulsion system (i.e., a balloon) so that a blimp
flies straight and far under its own power.
NOTE: In Blimp Jet, there are many more variables than in Sky Glider. Because it can take
many rounds of testing to get a blimp to travel a straight path, students must be patient
and be able to work precisely.
Preparation
Visit pbs.org/designsquad and download the following video clips from the
“Teacher’s Guide” page: Newton’s 3rd Law (1 minute) and Thrust & Newton’s
Laws (1 minute). Be prepared to project them.
Gather these materials (per team of two). See page 44 for suppliers.
• 12- to 16-inch latex
• balloon pump
• blimps from
party balloon (Long
• scissors
previous challenge
“rocket” balloons
• 6 drinking straws
• 4 sheets of paper
also work but hang
(narrow and wide)
• clear tape
down awkwardly.)
Make a blimp jet
To propel a blimp, make a
“jet.” Fit a straw into the
balloon’s neck. Seal it tightly
with tape.
Introduce the challenge (5 minutes)
• Tell students that today’s challenge is to add a jet propulsion system (in this
case, a party balloon) so their blimps fly under their own jet power. Hold up a
latex party balloon and a straw and make a jet. (See illustration.) (Mention that
the straw can help control how fast air escapes from the balloon.)
• How can you use this jet to provide thrust—a pushing force—to a blimp?
(Attach the jet to the blimp. To assure that the end of the jet stays pointing exactly
where students want it to point, they should attach it to a stable, easy-to-access
place, such as the frame connecting the two Mylar balloons. Demonstrate how to
use a pump to inflate the balloon. Point out how the straw lets you inflate the
balloon without having to detach the jet from the blimp.)
• What force does the jet’s thrust overcome? (Inertia and air resistance [i.e., drag])
© 2009 WGBH Educational Foundation.
Brainstorm (10 minutes)
Brainstorm Newton’s 3rd Law
• How is this jet an example of Newton’s 3rd Law? (Inside a sealed balloon, the
air pushes out equally on all sides, so there is equal force on all parts of the
balloon. But when you open the neck of the balloon, the air rushes out of the
hole. When this happens, one area of the inside surface—the area with the
hole—has less pressure on it than the other parts. The forces inside the
balloon are now unbalanced—there is a greater force pushing on the area
opposite the hole. So, the balloon moves in the direction of the greater force—
the area opposite the hole. Since the balloon is attached to the blimp, this
unbalanced force also pushes the blimp forward.)
• Which way should the straw point? (Opposite the direction students want the
blimp to travel. Very small adjustments of where the straw points have a
noticeable effect on how the blimp travels. This is why students must be willing
to work carefully and precisely.)
An inflated jet makes a
blimp look ungainly, but it
doesn’t significantly impair
the blimp’s flight.
39
• Watch both Newton’s Laws videos. In one, the Design Squad teams use
Newton’s 3rd Law to propel and steer a fan-propelled boat. In the other, they
build a flying football goalpost and grapple with balancing gravity and thrust.
Discuss how their blimp jet similarly provides thrust using an action-reaction
principle. Also point out the importance of reducing weight.
Brainstorm the design process
• Brainstorm good places to attach the jet. (A bottom-heavy blimp is more stable;
make sure the air stream flows freely and is not blocked by blimp parts.)
Students attach paper fins
to help a blimp fly straight.
This particular design won’t
travel as far as a more
streamlined blimp, due to air
resistance.
Summarize the problem to solve (5 minutes)
• Break the larger challenge into its sub-challenges. Ask: What are some of the
things you’ll need to figure out as you add a jet to your blimp? (Decide how to:
mount the jet; inflate the balloon; make minor adjustments easily; document each
test flight to understand how to modify the blimp and jet; etc.)
• To promote creative thinking and foster a sense of ownership, have students
pair up and brainstorm their own ways to add a jet.
Build, test, and redesign (30 minutes)
Here are some strategies for dealing with issues that may come up during building:
• Modify the balloon pump: Tips on commercial balloon pumps are too big to
fit into straws. Insert a thin straw into the pump tip and seal it with tape. Now
the thin straw can slip into a balloon jet’s straw.
• Make blimps neutrally buoyant: To compensate for the added weight of the
balloon jet, students will need to adjust their blimps to make them neutrally
buoyant again.
• Orient the blimp: Top-heavy blimps don’t stay level. Encourage students to
tape the balloon jet toward the bottom of the blimp.
• Tape the jet firmly in place: The balloon jet wiggles if kids tape it in only one
place. To anchor it well, students should tape it to the frame in at least two
places.
• Control the jet power: The amount of air leaving the balloon jet makes a
difference. If air escapes too quickly, the initial thrust is powerful, but it
rapidly peters out. If the air escapes too slowly, there’s too little thrust to
overcome inertia and air resistance. Students might need to modify the straw
to adjust the rate of the escaping air. Just make sure that the end of their
straw still fits into the pump. Overfilling balloons will, of course, pop them.
More air is not always the answer!
40
• A second class period? Students can achieve success in one class period
and have a fun, memorable experience with Newton’s 3rd Law. But devoting
two sessions to Blimp Jet will really let students refine their systems.
© 2009 WGBH Educational Foundation.
Accomplishing the
challenge—getting a blimp
to travel straight and
far—gives kids a real sense
of achievement.
MAKING
IT
REAL:
DRIVING HOME THE BREEZY BLIMPS UNIT
Overview: Students take their work beyond the walls of the classroom, using a
combination of presentations, videos, and discussion. They present their
blimps, discuss how they demonstrate the unit’s science concepts, point out
how they are thinking and working like engineers and discuss how engineering
is a field centered on making the world a better place.
SHOW KIDS THE
RELATED TV EPISODE
Preparation
Visit pbs.org/designsquad and download the following video clips from the
“Teacher’s Guide” page: Design Process: Teamwork (1½ minutes), Design
Process: Testing & Redesign (30 seconds), Band Cam Judging (4 minutes), and
the Mark Caylao engineer profile (2½ minutes). Be prepared to project them.
Raise student awareness of engineering (5 minutes)
Our world is molded by the engineering that surrounds us. Yet, many students are
unaware of what engineers do. Probe students’ ideas about engineering. Ask:
• What do engineers do? (List students’ ideas.)
• Then ask: What things in this room were probably designed or made by
engineers? (There is very little in the room other than the people, plants, and
dirt that does not bear the mark of an engineer.)
Relate students’ work to science and engineering (25 minutes)
View Band Cam Judging, in which team members discuss how to meet the Band
Cam challenge. Then ask:
• How did the teams create lift? (Varied the amount of helium; reduced the
frame’s weight; added propellers; redesigned based on testing; etc.)
Show students Band Cam,
the full-length Design Squad
TV episode related to the
Breezy Blimps unit, where
the Design Squad teams
design and build a remotecontrolled aerial camera
system to film a live concert.
Watch it online at: pbs.org/
designsquad.
• How could the teams redesign their faulty blimp? (Balance the weight better;
adjust propellers to provide more balanced thrust; make sure it’s neutrally
buoyant; increase the axis of rotation to reduce spin; lighten the load; etc.)
• How is the process you followed similar to the one the kids on Design Squad
did? (Both the students and the teams brainstormed lots of ideas, then built,
tested, and revised their blimps, and presented their designs to others.)
Show Design Process: Teamwork, in which the Design Squad teams discuss
frustrations inherent in teamwork. Then show Design Process: Testing &
Redesign, in which the Green Team, formerly at odds in Teamwork, works together
to come up with an effective solution to a problem. Have students present their
blimps. Use the following questions to explore key points in the video and unit:
• What could you suggest to help the Green Team work effectively together?
(Listen to each other; adjust one’s style to help things work smoothly; get input
from each team member; agree on a plan; choose roles; assign tasks; use
people’s strengths; etc.)
• What were some problems you solved as you built and tested your blimp?
© 2009 WGBH Educational Foundation.
• Was it harder to get a blimp to travel straight or to travel far? Why?
“ My students loved the
hands-on aspect of this
and really rose up to the
challenges. I learned that
I should not be afraid to
challenge my kids, and
I should do more
open-ended projects
with them.”
Harini A.
Belle Haven Elementary School
Menlo Park, CA
• What are some general characteristics that help a blimp work well?
(Lightweight; neutrally buoyant; long axis and fins to prevent spinning;
streamlined to minimize air resistance; etc.)
41
Meet an engineer (10 minutes)
• View the Mark Caylao video to introduce students to an engaging young
engineer involved in designing, building, and running one of the world’s largest
blimps. Of engineering, he says, “It’s the best job you can have. I love it!”
• Mark mentions that every day he uses things he learned in high school. Ask:
What subjects might you study to prepare to do the things Mark does? (Math,
science, and tech. ed. would help you understand how blimps work, and how to
design, build, operate, navigate, and maintain one.)
Students develop a
working knowledge of force
in Sky Floater, take their
understanding further in
Sky Glider, and explore the
relevance of the science and
engineering in Making It Real.
• What were some of the things Mark mentioned liking about being an engineer?
(He calls it the perfect job because he likes the traveling; being able to fly; being
part of the team that designs, builds, and operates blimps; and doing important
work, such as testing air quality and monitoring whales.)
Make the engineering real (10 minutes)
Use the following questions to help students see how the work they did relates to
engineering and see that engineers design things that improve people’s lives.
• Who might be interested in using blimps? (Blimps provide quiet, energy-efficient
transportation and can carry heavy loads and hover easily. They can be used in
logging operations, in search-and-rescue missions, and to carry cameras to
observe wildlife, conduct surveillance, and film TV broadcasts.)
• How might engineers be involved with blimps? (Designing sturdy, aerodynamic
blimps and efficient propulsion systems; inventing new, sturdy, lightweight
materials for making blimps; designing blimp-based transportation systems and
infrastructure, such as terminals, hangars, and manufacturing systems; finding
sources of gas to fill blimps; etc.)
• In what ways did you think and work like an engineer as you made your blimp?
(Used creativity; followed the design process to design, build, and test an
aerodynamic blimp that travels a straight path; applied science concepts—
buoyancy, force, and Newton’s laws; made a prototype of something people
want—an efficient mode of transportation; etc.)
Extension Ideas
• Share photos of your students’ designs and see what others have made. Visit
DS XCHANGE, Design Squad’s online community at pbs.org/designsquad.
Take our quick online
survey, and we’ll send you
a Design Squad class pack
(while supplies last—see
back cover for details).
Interdisciplinary Connections
• Math: Calculate how big a spherical balloon has to be to lift a pound, given that
the lift of helium is one ounce per cubic foot. Since the volume of this sphere
must be at least 16 cubic feet, then: 4⁄3 r3 = 16 cubic feet; r = 1.56 feet. (The
diameter must be at least 3.12 feet.)
• Social Studies: Research the history and current use of blimps in travel, law
enforcement, warfare, wildlife studies, search and rescue, and other fields.
42
© 2009 WGBH Educational Foundation.
TELL US
WHAT YOU THINK
• Using photos, contrast the design—the form and function—of a stunt plane
(built for sharp turns and quick maneuvers), supersonic jet (speed), and blimp
(distance, hovering, fuel economy). Focus on overall shape, axis of rotation
(short for stunts, long for steady flight), streamlining, fins and wings, and the
size and location of the cockpit or cabin.